Magnetic door holder and releasing device



1966 A. F. ISRAELSON ETAL 3, 3

MAGNETIC DOOR'HOLDER AND RELEASING DEVICE Filed March 6, 1963 INVENTORJ ARLO F. ISRAELSON WILLIAM F. SOSEY NELSON T. WALKER flmfxiw MAGNETIC DOOR This invention relates to door holders and, more particularly, to door holders for automatically holding fire or smoke doors open and for allowing them to close during emergency situations. It also is useful for automatically holding and releasing other closures.

Fire" door closers have previously been made which have actuating means in the form of a latch which allows the door to close when a fusible link is melted or is actuated by a solenoid means which, in turn, is actuated when the link is melted. The fusible links which ar currently being used for the aforesaid purpose are not completely satisfactory since they are not sensitive to smoke. They are also subject to mechanical difficulty.

When other devices such as electromagnets are used, they depend upon electricity to hold the door open. In an emergency, the main supply of electricity might not necessarily be discontinued; however, it would have to be it the electrorn'agnets were to perform their fiunction.

The device disclosed herein holds the door directly by magnetic force and the magnetic torce is interrupted when a signal is given by any one of the several methods normally used to indicate emergencies in buildings such as schools,,hospitals, hotels, etc.

The present device will hold the door open once the door is opened. It will hold the door open against the force of ordinary door closers. The door will stay open until automatically released by the mechanism disclosed herein. The door can be closed manually and reopened without special attention to the operating device.

It is, accordingly, an object of the present invention to provide an improved door holding device in combination with a signalling mechanism.

Another object of the invention is to provide an improved door holding device for safety doors.

A further object of the invention is to provide a door holdingdevice which is simple in construction, economical to manufacture, and simple and efficient to use.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawing:

FIG. 1 is a side view partly in cross section of a door holding device according to the invention;

FIG. 2 is a cross sectional view taken on line 2-2 of FIG. 1; and

FIG. 3 is an end view of the device.

Now with more particular reference to the drawing, a door holder assembly 11 is shown holding a door in open position against the force of a normal door closer. The door holder assembly is primarily mad up of a stop in the form ot' an armature 26 which is made of iron or other magnetic material and fixed to a door 25-. The armature is a separate part from the remainder of the device.

Normally, the armature 26 is attracted by magnets 13 which are supported between pole pieces 14. Thus, the

United States Patent magnets hold the door 25 in open position. The pole pieces 14 are slidably received between spacers 1-5. The spacers 15 are fixed to a cover 17. The spacers 15 are made of non-magnetic material such as stainless steel or the like.

T-he magnets 13 are fixed to a plunger 27 which is slidably supported in a solenoid 19. The solenoid .19 is in the form of a hollow cylinder of a usual type wound with Wire. When installed, a base plate 16 is fixed to a floor 29 or a wall or partition by means of a lag screw 30 or the like. Thus, in normal operation, the permanent magnet, through its pole pieces 14, exerts a magnetic force on the armature 26 and holds the door 25 open.

The solenoid 19 is electrically connected through wires 31 to a suitable source of power. A signalling device 32 is set up to close the circuit made up out the wires 31 when an emergency condition exists.

The cover 17 is held in place by a nut and screw assembly 20. When the door is held in open position, a flange 33 on the plunger rests against a butter '21. The Wires 31 extend through a back plate .18 and are insulated therefrom by a grommet 22.

Thus, when the switch actuated by the signalling device 32 closes, the solenoid 19 will be energized and it will pull the plunger 27 toward the solenoid 19 until the flange 33 engages the upper edge of the solenoid. The spacers 15 act as a stop tor the armature 26 when the plunger 27 is pulled into the solenoid. This will pull the pole pieces 14 to the dotted line position 34 and disengage from the armature 26, thereby allowing the conventional closing mechanism on the door 25 to move it to the closed position.

The foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A tastening device for holding a fixed member and a movable member together comprising a magnetic armature for attaching to said movable member,

an electrical solenoid supported on said fixed member,

stop means on said fixed member,

said solenoid having a movable core,

and a permanent magnet attached to said core for holding said armature in fixed relation to said fixed member,

said solenoid, when actuated, moving said permanent magnet relative to said stop means and thereby moving said armature into engagement \with said stop means and then moving said permanent magnet out of engagement with said armature whereby said movable member is released.

2. A control for a safety door for holding said door in open position comprising a door adapted to move from open to closed position, a magnetic armature fixed to said door, a solenoid fixed toa fixed member adjacent said door, spacers fixed! relative to said solenoid, a permanent magnet movably received between said spacers and adapted to hold said armature in engagement with said spacers, and means actuatable by said solenoid attached to said permanent magnet to move said permanent magnet between said spacers and out of engagement with said armature whereby said armature is released and said door can move to closed position.

3. In combination, a safety device and a door, said door having means comprising an armature made of magnetic material attached to said door, a solenoid, a plunger ---sl-ida1b'ly supported in said solenoid, apermanent magnet fixed relative to said plunger, and spacers on said safety device, said magnet being movable between said spacer-s,

said solenoid, when energized, pulling said magnet between said spacers out of attracting engagement With said door, saidsatety device comprising a base plate, a solenoid fixed to said-base plate, spacers fixed in spacedrelation to each other, a permanent magnet, and spacedpole pieces fixed to said permanent magnet and slidably received between said spacers With theouter ends of said pole pieces generally flush with the outer endsofsaid spacers, said armature being adapted to rest against said spacers urgedthereagainst when said door is in an open positionhysaid permanent magnet With said pole pieces engaging said armature, a plunger connected to said I 4 permanent magnet and being retractable by said solenoid to force said magnet and said pole pieces outofengagement with said armature and inward of the outer ends of said spacers.

5. The combination recited in claim 4 wherein said solenoid is connected to a circuit incorporating a switch sensitive to. an emergency situation.

vReferences Cited by the Examiner UNITED STATES PATENTS 709,607 9/1902 Podlesak 292. 201 X 2,441,913 5/1948 Taylor 292- 2 51.5 X 2,472,397 6/1949 Bennett 292 251.5 2,942,907 6/1960 Nagel et a1. 2921-2515 FOREIGN ,PATENTS 1,254,688 1/1961 France.

JOSEPH D. SEERS, Primary: E xamineia. M. HENSON WOOD, Ill -Examiner. 

3. IN COMBINATION, A SAFETY DEVICE AND A DOOR, SAID DOOR HAVING MEANS COMPRISING AN ARMATURE MADE OF MAGNETIC MATERIAL ATTACHED TO SAID DOOR, A SOLENOID, A PLUNGER SLIDABLY SUPPORTED IN SAID SOLENOID, A PERMANENT MAGNET FIXED RELATIVE TO SAID PLUNGER, AND SPACERS ON SAID SAFETY DEVICE, SAID MAGNET BEING MOVABLE BETWEEN SAID SPACERS, 